<!DOCTYPE html>
<title>Target element of ElementsInternals is held strongly and doesn't get GCed if there are no other references</title>
<meta name="timeout" content="long">
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/gc.js"></script>

<script>
customElements.define("x-foo", class extends HTMLElement {});

promise_test(async t => {
    const elementInternals = [];

    for (let i = 0; i < 1e5; i++) {
        const targetElement = document.createElement("x-foo");
        targetElement.attachShadow({ mode: "open" });
        elementInternals.push(targetElement.attachInternals());
    }

    await garbageCollect();
    await new Promise(r => t.step_timeout(r, 100));

    const allShadowRootsAreAlive = elementInternals.every(eI => eI.shadowRoot instanceof ShadowRoot);
    assert_true(allShadowRootsAreAlive);
});
</script>
